Conventionally, high voltage resistors have been used in the vicinity of power supplies for household appliances etc. High voltage resistors typically have been designed to have a resistance of 1 MΩ or greater and to withstand a voltage of 1 kV or greater. With such a high voltage resistor, while it is necessary to improve resistance accuracy and withstand voltage, efficiently raising the resistance accuracy is difficult due to the high resistance.
Technologies for increasing resistance accuracy of a resistor are disclosed in, for example, JP 2004-200424A, which discloses techniques for increasing resistance accuracy of a chip resistor. More specifically, multiple thick-film resistive elements having different sheet resistances are formed between a pair of electrodes, and laser trimming is performed to the respective thick-film resistive elements so as to provide a desired resistance. This resistance adjustment method serially connects the multiple resistive elements having different resistances and performs trimming to the resistive element, in order beginning with the element with the largest resistance (thick-film resistive element having the largest sheet resistance) so as to adjust the resistances. As a result, this technique not only makes the manufacturing process complicated due to formation of multiple thick-film resistive elements having different sheet resistances, but also, the resistance adjusting process is also complicated, contributing to the rising cost of manufacturing the resistor itself.